1. Field of the Invention
This invention relates to the art of keeping marine structures such as boats' pilings, bunkers, foundations, land implanted wood structures and the like free from barnacles, clams, oysters, mussels and like shell forming sea life forms from diverse, phyla including annelida, mollusca, arthropoda, insecta and rhodophyta which attach themselves or bore into such structures, without polluting the environment; and wooden structures on terrestrial environment subject to damage from boring pests such as termites, carpenter ants, wood bores and the like, and specifically deals with inhibiting materials for such structures which will not release long-lived toxic pollutants to the surrounding environment.
2. Description of the Prior Art
Heretofore fouling of marine structures by shell forming marine animals, such as above noted, and hereinafter generally termed barnacles, has been somewhat inhibited by toxic substances which pollute the aqueous environment. These toxic substances are not biodegradable and have become a major source of pollution and damage to aquatic life.
One type of barnacle inhibiting treatment has been the painting of the marine structures with a soft paint which continuously flakes off and thus provides an unstable surface receiving the barnacle. This type of treatment requires frequent painting and pollutes the aqueous environment with paint flakes. The treatment is only applicable for low speed boats adapted to be removed from the water and repainted at least once a year. The treatment is not suitable for most boats or other marine objects such as permanently immersed docks or bunkers. Thus, if the flaking paints are applied to the bottoms of relatively high speed fishing boats, pleasure boats, and the like, substantially all of the bottom paint is removed after a very few high speed runs. Also, the cost of annual painting of slow speed boats, such as tankers is prohibitive. Obviously, once the barnacle encrusted paint flakes off, the underlying structure such as the uncoated hull of a boat is a haven for barnacle encrustation.
Another known treatment for decreasing barnacle encrustation on marine structures has been the incorporation of generalized toxins in the paint such as heavy metal compositions such as tributyl tin, tributylamines, tributyl phosphate, arsenicals, and the like. These materials are toxic and not biodegradable. They pollute the surrounding environment to such an extent that aquatic life perishes and valuable oyster beds are soon destroyed.
It would thus be an improvement in this art to inhibit barnacle and the like encrustations on marine structures with long-lasting protective coatings containing non-toxic, biodegradable inhibitors which prevent the barnacles or the like from attaching themselves to the structures. These inhibitors are either repugnant to the barnacle itself or can destroy or neutralize its glue substance so as to stop the barnacle in the act of sitting down on the coating. The exposure of the non-toxic, biodegradable repellant is benign to the surrounding aqueous environment and the aquatic life therein.